The Agbar tower is a 35-story and 142 m high “small skyscraper”, located in Plaza de las Glorias.
It fits exactly in the acute angle formed by Diagonal Ave. and Badajoz St. The shape of the building emulates a fountain having a constant and perfectly stable pressure.
This is a very suitable image for the headquarters of a water company, reinforced by the idea that the building does not lean on the ground floor of the plot but it emerges from a crater in whose bed there is a water sheet.
Four basement floors fill the whole plot and include support functions and the parking. The auditorium, located in the first basement, appears in the surface as a hill in the undulating topography that makes up the open space planned around the tower.
The structure of the building is supported by an interior core and an exterior perimeter, both load-bearing. This arrangement allows floors to be free of structural columns. It is constructed by means of two oval concrete cylinders, which support a system of metallic beams. This system, in turn, supports a composite layer of metal and concrete deck.
The eccentricity of the core arranges the typical floor plant. The free area gets compressed in the lifts hall and gradually expands to the rest of the floor, generating the work area of the offices.
The exterior wall seems to be “pixelated” according to a mesh of almost square modules.
The window openings are irregularly arranged on this net, creating a “calligraphy” determined by the isolated accumulation of structural tensions, the flexibility of the offices and the density of perforations in the wall proportional to the sun radiation for every direction. Following this network, the façade shows modules of aluminium corrugated plate lacquered in 25 colours.
This coating protects a rockwool fixed to the exterior face of the wall and provides the shaft of the building with a backing, which gradually changes colour. It begins in the base with reddish shades, earthy like the ground they emerge from and ends in the upper floors with blue shades that blend with the sky in a dematerialisation exercise.
The exterior cylinder is upright just to the 18th floor where its generators start to curve to the interior, gradually diminishing their section up to the 26th floor where the concrete stops and the siding is completed with a metal structure glass dome. This dome ends the building with its 142 m of height.
The last 6 floors, built with concrete post-tensioned noggins of several thicknesses, are cantilevered from the central core, sharing the big space under the dome. These floors will be used for management purposes.
All the building is wrapped in a second skin of laminated glass slats with different degrees of transparency, blur the coloured façade behind, and behave as a vibrant veil shrouding the tower. The slats are treated and tilt depending on their location and a thorough study of the sun rays incidence.
Photo credits: Ateliers Jean Nouvel